1. Manuela Vélez Gaviria
Medicine Student – 3rd Semester
Universidad Pontificia Bolivariana
Medellin, 2012.

4.  Z-DNA found in
nucleosomes and in the
active transcription sites
is a step towards the
regulation of gene
expression.
 The schmidtea
mediterranea is a worm
able to regenerate
despite not having
centrosomes in the cells.

5. ELUSIVE Z-DNA FOUND ON NUCLEOSOMES
SCIENCEDAILY (JAN. 20, 2012)

6. ELUSIVE Z-DNA FOUND ON NUCLEOSOMES
SCIENCEDAILY (JAN. 20, 2012)
 Z-DNA is a possible
biologically active
form of
DNA, according to
research; Z-DNA is
present in
nucleosomes and at
sites of active
transcription.

7. ELUSIVE Z-DNA FOUND ON NUCLEOSOMES
SCIENCEDAILY (JAN. 20, 2012)
 Was discovered that is possible to
form Z-DNA from a family of
proteins (SWI/SNF) involved in the
remodeling of nucleosomes, that is
to say, change of position of the
nucleosome along the DNA.
 The SWI/SNF proteins have an
ATPase activity able to hydrolyze
ATP generating ADP+Pi and
energy which is used to remodel
the nucleosomes

8. ELUSIVE Z-DNA FOUND ON NUCLEOSOMES
SCIENCEDAILY (JAN. 20, 2012)
 The presence of Z-DNA in nucleosomes is very
important for the remodeling of chromosomes and
the regulation of transcription process.

9. STUDENT OBSERVATION
DNA is the structure in which life is contained, it has
attracted the interest of numerous researchers
throughout history, but although there have been
several and extraordinary advances, still missing
pieces to complete the puzzle, that is why, in my
opinion, this news is important because it gives a step
closer to mechanisms that can help the process of
transcription regulation fundamental in gene
expression.

10. FLATWORM FLOUTS FUNDAMENTAL RULE
OF BIOLOGY: WORM REGENERATES
WITHOUT CENTROSOME, A STRUCTURE
LONG THOUGHT NECESSARY FOR CELL
DIVISION
SCIENCEDAILY (JAN. 5, 2012)

11. FLATWORM FLOUTS FUNDAMENTAL RULE OF BIOLOGY: WORM
REGENERATES WITHOUT CENTROSOME, A STRUCTURE LONG THOUGHT
NECESSARY FOR CELL DIVISION
SCIENCEDAILY (JAN. 5, 2012)
 The centrosome is the
major microtubule
organizing center in
animal cells, which
contribute to the division
of chromosomes into
chromatids and
cytokinesis, it is for this
reason and its relation to
cell motility is regarded
as a necessary structure
in the cell division.

12. FLATWORM FLOUTS FUNDAMENTAL RULE OF BIOLOGY: WORM
REGENERATES WITHOUT CENTROSOME, A STRUCTURE LONG THOUGHT
NECESSARY FOR CELL DIVISION
SCIENCEDAILY (JAN. 5, 2012)
 The schmidtea
mediterranea is a worm with
a great capacity to
regenerate itself that’s why
it was selected to study
what happens in it after
manipulates their
centrosomes to destroy.
 Was observed that the
worm successfully
regenerated, which led to
even more detailed analysis
finally showed the absence
of centrosomes in the
species treated from the
beginning.

13. FLATWORM FLOUTS FUNDAMENTAL RULE OF BIOLOGY: WORM
REGENERATES WITHOUT CENTROSOME, A STRUCTURE LONG THOUGHT
NECESSARY FOR CELL DIVISION
SCIENCEDAILY (JAN. 5, 2012)
 The fact that the worm has the ability to regenerate
agility without the presence of centrosomes makes
you question the function of the centrosome in the
process of cell division… Is there something more
to be discovered?

14. STUDENT OBSERVATION
Mechanisms of self-replication are one of the
fundamental properties of eukaryotic cells and also
are the basis to understand several pathologies; I
think is really important to look into the role of the
centrosome in cell division and why a species with a
large capacity of regeneration, as it is the schmidtea
mediterranea, not have centrosomes, believed
absolutely necessary for the processes of cell
division and regeneration.

15.  Increasingly understand the processes of
replication, translation and transcription in this case, is the
possibility of regulating the expression of proteins and gene
expression, using this as a basis to reach the bottom of
hereditary diseases or defects related to any of the steps of
gene expression and find possible treatments.

16. Adequate cell replication and the control of this
constitute much of the health state of humans; an
alteration in the cell division can generate a lot of
diseases as cancer, therefore, knowledge and
research-oriented, self-replication mechanisms
provide alternatives for the treatment and possible
cure of the many diseases.

18. BIBLIOGRAPHY
 Elusive Z-DNA found on nucleosomes [ online ]
<http://www.sciencedaily.com/releases/2012/01/120
120183042.htm >[Tuesday January 24, 2012 ].
 Flatworm Flouts Fundamental Rule of Biology:
Worm Regenerates Without Centrosome, a
Structure Long Thought Necessary for Cell Division
[ online ]
<http://www.sciencedaily.com/releases/2012/01/120
105174220.htm> [Tuesday January 24, 2012 ].